Tunable optical filters using cascaded etalons
OwnerAaron J. Zilkieinventor
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Abstract
A temperature-tuned dielectric-slab-etalon scanning spectrometer that is low cost and simple to fabricate uses cascaded etalon modules, each module comprising a Fabry-Perot (FP) etalon having a relatively small Free Spectral Range (FSR), with at least two modules provided with a temperature control. According to the invention, the multiple FP modules produce Vernier tuning control. In these devices, the tuning temperature range is typically less than 10° C., and the required slab thickness may be less than 1 mm. This reduces fabrication and material requirements, and results in lower device cost and improved reliability.
Claims20
Method for tuning an optical filter wherein the optical filter comprises at least two Fabry-Perot etalon modules N1 and N2, the method comprising the steps of cycling the temperature of the modules through S cycles, wherein each of the S cycles comprises simultaneously changing the temperature TN1 of the N1 module over a range of TΔ1 from T1N1 to T2N1 and changing the temperature TN2 of the N2 module by TΔ2 from T1N2 to T2N2, where the temperature difference TN2−TN1 is fixed during each cycle and changes from cycle to cycle.
Method for tuning an optical filter wherein the optical filter comprises at least two Fabry-Perot etalon modules N1 and N2, the method comprising the steps of cycling the temperature of the N1 module through S=1 cycle, wherein the S cycle comprises changing the temperature N1 module over a range of TΔ1 from T1N1 to T2N1 while maintaining the temperature of the N2 module fixed.
An optical filter comprising:
- a Fabry-Perot etalon module N1,
- an N1 temperature control for controlling the temperature of module N1,
- a Fabry-Perot etalon module N2, spaced from and optically aligned with module N1,
- an N2 temperature control for controlling the temperature of module N2, wherein temperature controls N1 and N2 simultaneously cycle the temperature of the modules through S cycles, wherein each of the S cycles comprises simultaneously changing the temperature TN1 of the N1 module over a range of TΔ1 from T1N1 to T2N1 and changing the temperature TN2 of the N2 module by TΔ2 from T1N2 to T2N2, where the temperature difference TN2−TN1 is fixed during each cycle and changes from cycle to cycle.
Dependencies are inferred from the claim text.